docs: def oldest_peer(peers):
      """Determines who the oldest peer is by comparing unit numbers."""
      local_unit_no = int(os.getenv('JUJU_UNIT_NAME').split('/')[1])
      for peer in peers:
          remote_unit_no = int(peer.split('/')[1])
          if remote_unit_no < local_unit_no:
              return False
      return True